Pipe injectors and methods of introducing tubing into or removing it from a well bore

ABSTRACT

A pipe injector assembly is disclosed, comprising: a pipe injector that includes at least three tubing drive units radially arranged around a feed axis along which tubing is fed, the tubing drive units having drive components that are laterally displaceable between a closed condition in which the drive components drivingly engage said tubing and an open condition in which the lateral spacing between the drive components is increased to permit the passage of a coupling of the tubing. A pipe injector assembly is also disclosed, comprising: a pipe injector that includes at least two tubing drive units radially arranged around a feed axis along which tubing is fed, the tubing drive units having drive components that are displaceable between a closed condition in which the drive components drivingly engage said tubing and an open condition in which the spacing between the drive components is increased to permit the passage of a coupling of the tubing; and a set of tubing slips that are laterally displaceable between a closed condition in which the tubing slips grip the tubing and an open condition in which the lateral spacing between the tubing slips is increased to permit the passage of the coupling; in which the pipe injector is displaceable longitudinally relative to the set of tubing slips.

TECHNICAL FIELD

This document relates to pressurised well bores. More particularly itrelates to a method of introducing tubing into or removing it from awell bore. It further relates to a pipe injector assembly suitable foruse in the method.

BACKGROUND

Introducing tubing into, or removing tubing from, a well bore underpressure requires that the tubing be gripped at all times, in order toprevent the tubing from being blown out of the well. Further, the tubingmay require the same gripping after the weight of the tubing in the wellhas surpassed the pressure of the well, in order to prevent the tubingfrom falling into the well.

Coupled pipe, also known as jointed or collared tubing, incorporateslengths of tubing connected end to end by couplings that have a widerouter diameter than the lengths of tubing themselves. The presence ofthese couplings makes injection with a conventional coiled tubing chaininjector difficult.

SUMMARY

According to an embodiment, there is provided a method of introducingtubing into or removing it from a well bore which includes: displacingtubing into or out of a well bore by a pipe injector having drivecomponents which drivingly engage the tubing, and displacing at leastsome of the drive components outwardly to permit a coupling in thetubing to pass between the drive components; and once the coupling haspassed the pipe injector, displacing the drive components inwardlydrivingly to engaging the tubing. The pipe injector may have at leastthree tubing drive units radially arranged around the tubing, the tubingdrive units having the drive components that drivingly engage thetubing.

The Inventor believes that the embodiments of this document will findapplication particularly though not necessarily exclusively inpressurised well bores.

In an embodiment, the method may include making use of a pipe injectorwhich is relatively displaceable longitudinally, for example relative tothe tubing feed direction. Hence, the method may include, when the drivecomponents of the pipe injector are displaced outwardly, displacing thepipe injector longitudinally in a direction opposite to a feed directionof the tubing, and once the drive components have passed the coupling,displacing the drive components inwardly to drivingly engage the tubing.When the drive components are displaced inwardly they drivingly engagethe tubing on the opposite side of the coupling. In some embodiments,the pipe injector is displaceable longitudinally relative to a set oftubing slips. These embodiments may further include: displacing the setof tubing slips outwardly and displacing the tubing longitudinally usingthe pipe injector to permit a coupling in the tubing to pass the set oftubing slips; and displacing the drive components outwardly and grippingthe tubing longitudinally using the set of tubing slips tolongitudinally displace the drive components relative to the set oftubing slips to permit a coupling in the tubing to pass the drivecomponents.

The pipe injector may be relatively longitudinally displaceable underthe influence of a pressurized fluid, typically hydraulically.

The method may include, prior to displacing the drive componentsoutwardly, locking the tubing releasably in position. Locking the tubingreleasably in position may include displacing tubing slips intoengagement with the tubing. The method may further include, once thedrive components of the pipe injector have been displaced inwardly intodriving engagement with the tubing, releasing the tubing by displacingthe tubing slips out of engagement with the tubing.

In another embodiment of this document, the method may include makinguse of an upper pipe injector and a lower pipe injector positioned belowand longitudinally in register with the upper pipe injector, the methodincluding displacing drive components of one pipe injector outwardly anddisplacing the tubing longitudinally using the other pipe injector orinjector to permit a coupling in the tubing to pass said one pipeinjector or injector. Hence, normally, the tubing may be fed into thewell bore using both injectors. As a coupling approaches the upperinjector, its tube engaging or drive components are displaced outwardlyand the tubing is fed into the well by the lower injector. When thecoupling has passed the upper injector, its drive components aredisplaced inwardly drivingly to engage the tubing above the coupling.The tubing drive components of the lower injector are then displacedoutwardly permitting the coupling to pass therebetween, after which theyare displaced inwardly drivingly to engage the tubing above thecoupling. When tubing is being removed from the well bore the reverseprocedure will be followed.

According to another embodiment there is provided a pipe injectorassembly which includes: at least one pipe injector that includes atleast two tubing drive units radially arranged around a feed axis alongwhich tubing is fed, the drive units including drive components that arelaterally displaceable between a closed condition in which the drivecomponents drivingly engage said tubing and an open condition in whichthe lateral spacing between the drive components is increased to permitthe passage of a coupling connecting lengths of tubing togethertherebetween.

The pipe injector may include at least three tubing drive units arrangedfor example equiangularly around the feed axis.

The drive components may include, associated with each tubing driveunit, a chain guide, an endless feed chain supported on the chain guideand configured in the closed condition drivingly to engage said tubingand a chain drive arrangement. The chain may be contoured and configuredto engage the tubing with a friction bite.

In an embodiment of this document, the pipe injector may be relativelydisplaceable longitudinally, for example relative to the feed axis. In afurther embodiment, the assembly may include a support structure and ajacking arrangement whereby the pipe injector is mounted on the supportstructure. The jacking arrangement may include a plurality ofhydraulically actuated piston and cylinder arrangements. In someembodiments, the pipe injector is displaceable longitudinally relativeto a set of tubing slips that are displaceable between a closedcondition in which the tubing slips grip the tubing and an opencondition in which the spacing between the tubing slips is increased topermit the passage of the coupling.

In another embodiment, the assembly may include an upper pipe injectorand a lower pipe injector positioned below and longitudinally inregister with the upper injector, the tubing drive units of the upperinjector being displaceable from their closed to their open conditionindependently of those of the lower injector and vice versa.

The assembly may include a sensor arrangement for sensing the positionof a coupling in the tubing and for controlling the operation of eachpipe injector in response thereto.

These and other aspects of the device and method are set out in theclaims, which are incorporated here by reference.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments will now be described with reference to the figures, inwhich like reference characters denote like elements, by way of example,and in which:

FIGS. 1 to 6 show a side view of a pipe injector assembly in accordancewith embodiments of this document illustrating sequentially, the passageof a coupling connecting together lengths of tubing through the pipeinjector assembly;

FIGS. 7 to 11 show another pipe injector assembly in accordance withembodiments of this document illustrating sequentially the passage ofcoupling connecting together lengths of tubing therethrough;

FIG. 12 shows, on an enlarged scale, a side view of part of the pipeinjector assembly of FIGS. 7 to 11; and

FIG. 13 shows a sectional elevation of the part of the pipe injectorshown in FIG. 12.

FIG. 14 shows another embodiment of a pipe injector assembly with astationary pipe injector and a movable set of tubing slips.

DETAILED DESCRIPTION

Immaterial modifications may be made to the embodiments described herewithout departing from what is covered by the claims.

In FIGS. 1 to 6 of the drawings, reference numeral 10 refers generallyto a pipe injector assembly in accordance with embodiments of thisdocument.

Referring to FIGS. 2 and 3, a pipe injector assembly 10 is illustratedcomprising pipe injector 14. Pipe injector 14 includes at least twotubing drive units 36 radially arranged around a feed axis 18 alongwhich tubing 62 is fed. The tubing drive units 36 have drive components,described in more detail below, which are displaceable between a closedcondition (shown in FIG. 2) in which the drive components drivinglyengage the tubing 62 and an open condition (shown in FIG. 3) in whichthe spacing between the drive components is increased to permit thepassage of a coupling 70 of the tubing 62.

Referring to FIGS. 1 and 2, in some embodiments the pipe injectorassembly 10 includes a set of tubing slips 20 that are laterallydisplaceable between a closed condition (shown in FIG. 2) in which thetubing slips 20 grip the tubing 62 and an open condition (shown inFIG. 1) in which the lateral spacing between the tubing slips 20 isincreased to permit the passage of the coupling 70. In theseembodiments, the pipe injector 14 is displaceable longitudinallyrelative to the set of tubing slips 20.

Referring to FIGS. 1-6, the pipe injector assembly 10 may include ajacking arrangement, generally indicated by reference numeral 16,between the set of tubing slips 20 and the pipe injector 14, whereby thepipe injector 14 is displaceable relative to the tubing slips 20. Thepipe injector 14 may also be displaceable relative to a supportstructure 12 longitudinally relative to a feed axis 18 as described inmore detail herebelow.

Mounted below the support structure 12 may be set of tubing slips 20, anannular Bop 22, a single gate 24, an equalise/bleed off spool 26, asingle gate Bop 28 and a well head 30. A rotating segment 21 may bepositioned between the slips 20 and the Bop 22 that permits the pipeinjector 14 to rotate about the axis 18 thereby enabling the assembly tobe used for drilling.

The support structure 12 may include three platforms 32 (two of whichare visible in FIGS. 1 to 6 of the drawings) which may be displaceableradially in the direction of arrows 34 between a closed condition (shownin FIGS. 1, 2, 5 and 6 of the drawings) and an open condition (shown inFIGS. 3 and 4 of the drawings). The pipe injector 14 may include threetubing drive units, generally indicated by reference numeral 36, one ofwhich may be mounted on each of the platforms 32 by means of ahydraulically actuated piston and cylinder arrangement 38. The threepiston and cylinder arrangements 38 together may form the jackingarrangement 16, although other jacking arrangements are possible. Thetubing drive units 36 may comprise endless chain tubing drive units asshown. In these embodiments, each drive unit 36 may include one or moredrive component, such as a chain guide 40, an endless feed chain 50, anda chain drive arrangement, which may include drive sprocket 44. Thechain guide 40 may comprise a pair of spaced apart plates 42 betweenwhich a drive sprocket 44 and a pair of idler sprockets 46, 48 aremounted. An idler sprocket may be mounted above the drive sprocket 44,with the idler sprocket 46 mounted horizontally in line with the drivesprocket 44 such that endless chain 50 may be supported on thesprockets, 44, 46, 48 to define a generally triangular path having avertical run 52, a horizontal run 54 and an inclined run 56. A hydraulicmotor 58 (FIG. 11) may be mounted on one of the plates 42 and drivinglyconnected to the drive sprocket 44 in order to drive the chain 50 in thedirection of arrow 60. The motor may be connected to any one of thesprockets. Further, more than one drive motor may be used, e.g. up tothree drive motors could be drivingly connected to the sprockets.

A method of introducing tubing 62 into or removing it from well bore 30may comprise providing set of tubing slips 20 and pipe injector 14 forexample as shown in FIGS. 1-6. Referring to FIGS. 5-6, the set of tubingslips 20 may be displaced outwardly and the tubing 62 longitudinallydisplaced using the pipe injector 14 to permit coupling 70 in the tubing62 to pass the set of tubing slips 20. In use, in order to inject tubing62 into a well bore, the drive units 36 may be positioned in theirclosed condition such that the chains 50 engage the tubing 62 alongtheir vertical runs 52 and feed the tubing along the feed axis 18 in thedirection of arrow 66 through the tubing slips 20 which, as shown inFIG. 1 of the drawings, are in their open position, the rotating segment21, the Bop 22, the gate 24, the bleed off spool 26, the Bop 28 and thewell head 30 into the well. Referring to FIGS. 3-4, the drive componentsmay be displaced outwardly and the tubing 62 gripped longitudinallyusing the set of tubing slips 20 to longitudinally displace the drivecomponents relative to the set of tubing slips 20 to permit coupling 70in the tubing 62 to pass the drive components of pipe injector 14. Asillustrated, this stage may comprise gripping the tubing 62 using theset of tubing slips 20 and longitudinally displacing the drivecomponents of pipe injector 14 relative to the set of tubing slips 20using jacking arrangement 16 between the tubing drive units and the setof tubing slips. The drive components may be displaced longitudinallyrelative to a tubing feed direction 66 (shown in FIG. 1).

As described, the pipe injector 14 may be displaceable longitudinallyrelative to the feed axis 18 when in the open condition. Referring toFIG. 14, an embodiment is illustrated where pipe injector 14 is fixed tothe well head 30. In this embodiment, slips 20 are longitudinallydisplaceable relative to feed axis 18, and may act as a pipe injectorthat longitudinally displaces tubing 62, for example when pipe injector14 is not drivingly engaged with tubing 62.

Injector assembly 10 may have a sensor 68 configured to sense thepresence of a coupling 70. Sensor 68 may be mounted on top of one of thedrive units 36 and configured to sense the presence of a coupling 70connecting together lengths of tubing. The sensor 68 may be part of acontrol system configured such that, upon receipt of a signal from thesensor 68 indicative of the presence of a coupling 70 adjacent to thedrive units 66, operation of the hydraulic motors 58, is stopped. Thetubing slips 20 may be displaced inwardly to grip the tubing 62 (FIG.2). The drive units 36 may be then displaced radially outwardly by meansof openers 72 into their open condition shown in FIG. 3 of the drawings,in which they are clear of the tubing 62. The piston and cylinderarrangements 38 may be then extended in order to displace the driveunits 36 past the coupling 70, as shown in FIG. 4 of the drawings. Inthis position, the drive units may be once again displaced inwardly intodriving engagement with the tubing 62 above the coupling 70 and thetubing slips 20 may be displaced into their open position (asillustrated in the FIG. 5 of the drawings). The piston and cylinderarrangements 38 may be returned to their retracted positions, shown inFIG. 6 of the drawings, and the hydraulic motors 58 may be operated inorder to drive the chains 50 and feed the tubing into the well bore.

Further, in order to remove tubing from the well bore, the reverseprocedure to that described above may be followed. In particular, thedrive units 36 may be positioned in their closed condition such that thechains 50 engage the tubing 62 and displace it in a direction oppositeto the direction of arrow 66.

A sensor 90 may be mounted below one of the drive units 36 andconfigured to sense the presence of a coupling 70. The sensor 90 may bepart of the control system and accordingly, when a coupling 70 is sensedby the sensor 90, operation of the hydraulic motors 58, is stopped. Thepiston and cylinder arrangements 38 may be then extended in order todisplace the drive units and the tubing into the position shown in FIG.5 of the drawings. The tubing slips 20 may be displaced to their closedposition and the drive units 36 may be displaced radially outwardly bymeans of the opener 72 into their open condition, shown in FIG. 4 of thedrawings, in which they are clear of the tubing 62. The piston andcylinder arrangements 38 may be then retracted in order to displace thedrive units 36 past the coupling 70 as shown in FIG. 3 of the drawings.In this position, the drive units may be once again displaced inwardlyinto driving engagement with the tubing 62 below the coupling 70 and thetubing slips 20 may be displaced to their open position and thehydraulic motors 58 may be operated in order to drive the chains 50 andremove the tubing from the well bore.

Reference is now made to FIGS. 7 to 13 of the drawings, in whichreference numeral 200 refers generally to another pipe injector assemblyin accordance with embodiments of this document and, unless otherwiseindicated, the same reference numerals used above are used to designatesimilar parts.

In some embodiments pipe injector 14 includes at least three tubingdrive units 36 radially arranged, for example equiangularly (shown inFIG. 12), around a feed axis (shown as axis 18 in FIG. 1). The use ofthree or more tubing drive units is advantageous because it prevents orreduces undesired bending or arc-ing of the tubing 62 passed through.

In the embodiment, shown, instead of or in addition to making use of thejacking arrangement 16, the assembly includes at least two injectors,for example an upper injector 202 that may be pipe injector 14, and asecond pipe injector 204, which is positioned below and in register withthe upper injector along the feed axis 18. The structure of the upperand lower injectors 202, 204 may be substantially identical to theinjector 14, and for the sake of brevity, is not described in anydetail. It should, however, be noted that, in the embodiment shown, theinjector 204 may be inverted, however, it need not be.

Further, it is important to note, that the drive components of driveunits 36 of the upper injector 202 may be displaceable radially betweentheir closed and open conditions, independently of the drive componentsof drive units 36 of the lower injector 204 and vice versa.

A method of introducing tubing 62 into or removing it from well bore 30comprises displacing tubing into or out of a well bore by pipe injector14, as shown in FIG. 7. In use, as illustrated in FIG. 7 of thedrawings, when feeding tubing into the well bore, the drive units 36 ofboth the upper and lower injectors 202, 204 may be in their closedconditions such that their chains 50 drivingly engage and feed thetubing 62 into the well bore. Referring to FIG. 8, at least some of thedrive components of the tubing drive units 36 are displaced outwardly topermit a coupling 70 in the tubing 62 to pass between the drivecomponents. As illustrated, when the drive components of the upperinjector 202 are displaced outwardly, the lower injector 204 maydisplace the tubing 62 longitudinally to permit coupling 70 in thetubing to pass the upper injector 202. This may be initiated with sensor68. When the sensor 68 senses the presence of a coupling 70 immediatelyadjacent the upper end of the upper injector 202, the drive units 36 ofthe upper injector 202 may be displaced to their open condition (shownin FIG. 8) by the associated openers 72 whilst the lower injector 204continues to feed the tubing into the well. The spacing between thedrive units 36 of the upper injector 202 is such that the coupling 70passes, with clearance, therebetween. Referring to FIG. 9, once thecoupling 70 has passed the drive units of the pipe injector, the drivecomponents may be displaced inwardly to drivingly engage the tubing 62.When the drive components of the lower pipe injector 204 are displacedoutwardly, the tubing 62 may be longitudinally displaced using the upperpipe injector 202 to permit coupling 70 in the tubing 62 to pass thelower pipe injector 204. Again, this may be done with sensors. Sensorsmay sense the presence of a coupling clearing either injector in use, inorder to move the respective injector back into the closed position.When a second sensor (not shown), positioned between the upper and lowerinjectors 202, 204 senses the presence of the coupling 70 which isindicative of the fact that the coupling has passed the upper injector202, the drive units 36 of the upper injector 202 may be displaced totheir closed positions in which they drivingly engage the tubing abovethe coupling 70. The drive units 36 of the lower injector 204 may bethen displaced to their open condition (shown in FIG. 10 of thedrawings) by the associated openers 72 and the upper injector 202 feedsthe tubing into the well bore. When the coupling 70 has passed the lowerinjector 204 its drive units 36 may be once again returned to theirclosed condition (shown in FIG. 11) and the tubing may be fed into thewell by means of both the upper and lower injectors 202, 204.

It will be appreciated that the pipe injector assembly 200 can also beused to remove tubing from the well bore by following the reverseprocedure described above. To this end, suitable sensors will beprovided in order to sense the presence of a coupling below the lowerinjector 204 and between the injectors 202, 204.

The Inventor believes that the embodiments of this document willfacilitate the injection of tubing into and removal of tubing from awell bore in an efficient and automated fashion thereby leading toimproved productivity.

In the claims, the word “comprising” is used in its inclusive sense anddoes not exclude other elements being present. The indefinite article“a” before a claim feature does not exclude more than one of the featurebeing present. Each one of the individual features described here may beused in one or more embodiments and is not, by virtue only of beingdescribed here, to be construed as essential to all embodiments asdefined by the claims.

1. A pipe injector assembly, comprising: a pipe injector that includesat least three tubing drive units radially arranged around a feed axisalong which tubing is fed, the tubing drive units having drivecomponents that are laterally displaceable between a closed condition inwhich the drive components drivingly engage said tubing and an opencondition in which the lateral spacing between the drive components isincreased to permit the passage of a coupling of the tubing.
 2. The pipeinjector assembly of claim 1 in which the tubing drive units compriseendless chain tubing drive units.
 3. The pipe injector assembly of claim2 in which the drive components associated with each endless chaintubing drive unit comprise: a chain guide; an endless feed chainsupported on the chain guide and configured in the closed condition todrivingly engage said tubing; and a chain drive arrangement.
 4. The pipeinjector assembly of claim 1 in which the tubing drive units arearranged equiangularly around the feed axis.
 5. The pipe injectorassembly of claim 1 in which the pipe injector is displaceablelongitudinally relative to the feed axis when in the open condition. 6.The pipe injector assembly of claim 1 in which the pipe injector isdisplaceable longitudinally relative to a set of tubing slips that aredisplaceable between a closed condition in which the tubing slips gripthe tubing and an open condition in which the spacing between the tubingslips is increased to permit the passage of the coupling.
 7. The pipeinjector assembly of claim 1 further comprising a second injectorpositioned below and in register with the pipe injector along the feedaxis.
 8. The pipe injector assembly of claim 7 in which the second pipeinjector comprises at least two tubing drive units radially arrangedaround the feed axis, the tubing drive units of the second pipe injectorincluding drive components that are displaceable between a closedcondition in which the drive components drivingly engage said tubing andan open condition in which the spacing between the drive components isincreased to permit the passage of the coupling; in which the tubingdrive units of the pipe injector are displaceable from the closedcondition to the open condition independently of the tubing drive unitsof the second pipe injector.
 9. The pipe injector assembly of claim 8 inwhich the second pipe injector comprises at least three tubing driveunits radially arranged around the feed axis.
 10. The pipe injectorassembly of claim 8 in which the tubing drive units of the second pipeinjector comprise endless chain tubing drive units.
 11. The pipeinjector assembly of claim 1 further comprising a sensor configured tosense the presence of a coupling connecting.
 12. A method of introducingtubing into or removing it from a well bore, the method comprising:displacing tubing into or out of a well bore by a pipe injector havingat least three tubing drive units radially arranged around the tubing,the tubing drive units having drive components which drivingly engagethe tubing; displacing at least some of the drive components of thetubing drive units outwardly to permit a coupling in the tubing to passbetween the drive components; and once the coupling has passed the driveunits, displacing the drive components inwardly to drivingly engage thetubing.
 13. The method of claim 12 further comprising: when the drivecomponents of the pipe injector are displaced outwardly, displacing thepipe injector longitudinally in a direction opposite to a feed directionof the tubing; and once the drive components have passed the coupling,displacing the drive components inwardly to drivingly engage the tubing.14. The method of claim 12 in which a second pipe injector is positionedbelow and in register with the pipe injector along the feed axis, thesecond pipe injector having at least two tubing drive units includingdrive components that drivingly engage the tubing, the drive componentsbeing radially arranged around the tubing, the method furthercomprising: 1displacing drive components of the pipe injector outwardlyand displacing the tubing longitudinally using the second pipe injectorto permit a coupling in the tubing to pass the pipe injector; anddisplacing drive components of the second pipe injector outwardly anddisplacing the tubing longitudinally using the pipe injector to permit acoupling in the tubing to pass the second pipe injector.
 15. A pipeinjector assembly, comprising: a pipe injector that includes at leasttwo tubing drive units radially arranged around a feed axis along whichtubing is fed, the tubing drive units having drive components that aredisplaceable between a closed condition in which the drive componentsdrivingly engage said tubing and an open condition in which the spacingbetween the drive components is increased to permit the passage of acoupling of the tubing; and a set of tubing slips that are laterallydisplaceable between a closed condition in which the tubing slips gripthe tubing and an open condition in which the lateral spacing betweenthe tubing slips is increased to permit the passage of the coupling; inwhich the pipe injector is displaceable longitudinally relative to theset of tubing slips.
 16. The pipe injector assembly of claim 15 furthercomprising a jacking arrangement between the set of tubing slips and thepipe injector.
 17. The pipe injector assembly of claim 16 in which thejacking arrangement comprises a hydraulic piston and cylinderarrangement.
 18. A method of introducing tubing into or removing it froma well bore, the method comprising: providing a set of tubing slips anda pipe injector having at least two tubing drive units radially arrangedaround the tubing, the tubing drive units having drive components whichdrivingly engage the tubing; displacing the set of tubing slipsoutwardly and displacing the tubing longitudinally using the pipeinjector to permit a coupling in the tubing to pass the set of tubingslips; and displacing the drive components outwardly and gripping thetubing longitudinally using the set of tubing slips to longitudinallydisplace the drive components relative to the set of tubing slips topermit a coupling in the tubing to pass the drive components.
 19. Themethod of claim 18 in which gripping further comprises gripping thetubing using the set of tubing slips and longitudinally displacing thedrive components relative to the set of tubing slips using a jackingarrangement between the tubing drive units and the set of tubing slips.20. The method of claim 18 in which the drive components are displacedlongitudinally relative to a tubing feed direction.